Dynamic nuclear polarization weighted spectroscopy of multispin electronic-nuclear clusters

Nuclear spins and paramagnetic centers in a solid randomly group to form clusters featuring nearly-degenerate, hybrid states whose dynamics are central processes involving nuclear spin-lattice relaxation diffusion. Their characterization, however, has proven notoriously difficult mostly due their relative isolation comparatively low concentration. Here, we combine field-cycling experiments, optical spin pumping, variable radio-frequency (RF) excitation probe transitions between multi-spin formed by strongly coupled electronic diamond. Leveraging bulk nuclei as collective time-integrating sensor, the response of these simultaneously vary applied magnetic field RF reconstruct multi-dimensional spectra. We uncover complex polarization patterns alternating sign that qualitatively capture through analytical numerical modeling. Our results unambiguously expose impact strongly-hyperfine-coupled can have on crystal, inform future routes cluster control detection.